He is being charged following the discovery of the bodies of 57-year-old Anthony Agius from Rabat and 51-year-old Dennis Mifsud from Siġġiewi in an alleyway in the Kunċizzjoni area of Rabat.
Ciantar allegedly felt the scene after the shootings which led to a manhunt which ended with his arrest in Mosta.
Ciantar appeared in court at 1pm before magistrate Rachel Montebello.